Transmission type spatial light modulator and transmission type spatial light modulation array device

ABSTRACT

A transmission type spatial light modulatoris equipped with a minute transparent optical member for deflecting light in a direction different from an incident direction of incident light and emitting the light, a support member for supporting the minute transparent optical member at a midair position so that the light emission face can be inclined with respect to a plane perpendicular to a travel direction of incident light L 1 , and a driving member for obliquely displacing the minute transparent optical member by an electrical mechanical operation to vary the emission direction of light from the minute transparent optical member.

This application is based on Japanese Patent application JP 2004-168097,filed Jun. 7, 2004, the entire content of which is hereby incorporatedby reference. This claim for priority benefit is being filedconcurrently with the filing of this application.

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

The present invention relates to a transmission type spatial lightmodulator and a transmission type spatial light modulation array device.

2. Description of the Related Art

A light deflector is known as a device for controlling any one of anangle or position of a light propagation direction or both the angle andthe position with respect to the time. As the light deflector are knowna reflection type mechanical type light deflector for deflecting lightby swinging a reflection mirror, and a transmission type mechanical typelight deflector for deflecting light by rotating a prism or the like. Inthe reflection type, incident light and emission light exist at the sameside with respect to the device. On the other hand, in the transmissiontype, the incident light and the emission light exist at the differentsides with respect to the device, and thus it has an advantage that theconstruction of the peripheral optical system is simple. For example, inthe construction disclosed in JP-A-11-249037, PBS (Polarized beamsplitter) is disposed to make light from a light source incident to areflection type spatial light modulation array device. However, it isnot needed in the transmission type. In the construction disclosed inJP-A-2001-201716, surface reflection light from a reflection typespatial light modulation array device (micro-mirror device) isunnecessary light, and it reduces the contrast, so that a lightseparating prism provided to prevention the reduction of the contrastenlarges the device.

In the reflection type, since the incident light and the emission light(deflected light) and the unnecessary light such as the surfacereflection light based on the incident light exist at the same side withrespect to the device, it is difficult to freely set the directions ofON light (effective light) and OFF light (unnecessary light) in theemission light (deflected light). For example, when great importance isplaced on the contrast, it is required that the directions of the ONlight and the unnecessary light such as the surface reflection light,etc. are different from each other. On the other hand, in thetransmission type, the unnecessary light such as the surface reflectionlight, etc. based on the incident light exists at the incident side, andonly the emission light (deflected light) exists at the emission side,so that it is possible to freely set the directions of the ON light andthe OFF light in the emission light. Therefore, the degree of freedom ofthe design of a peripheral optical system is enhanced, and the latitudeof the optical precision is relatively enhanced. An example of aconventional transmission type mechanical light deflector will bedescribed. In this specification, “deflection” means the function ofcontrolling any one of the angle and position of the light propagationdirection or both the angle and the position with respect to the time.

An optical switch disclosed in JP-A-2002-23072 is equipped with aplurality of light input/output portions 1 comprising optical fibers fortransmitting optical signals, deflecting means (wedged prism) 3 fordeflecting a light beam corresponding to an optical signal incident fromthe light input/output portion 1 and selecting an optical fiber of thelight input/output portion 1 to which the optical signal should betransmitted, and light converging means 5 a, 5 b for converging thelight beam corresponding to the optical signal incident/emitted to/fromthe optical input/output portion 1 to set the optical beam to acollimated beam, and converging the light beam emitted from thedeflecting means 3 into the optical fiber of the light input/outputportion 1 selected by the deflecting means 3 as shown in FIG. 36.

According to the optical switch, since a light beam is deflected and anoptical fiber to which the light should be made incident is selected byrotating the wedge-shaped prism 3, there can be achieved effects thatthe optical fiber itself is not required to be moved, and thus theoptical fiber can be prevented from being damaged by the movement of theoptical fiber, so that the reliability of light transmission can beenhanced.

As shown in FIGS. 37A to 37B, a beam deflecting device disclosed inJP-A-2000-180742 is equipped with a rotating prism body 7 that is formedof an optical material and has two or more pairs of a light incidentface and a light emission face which are arranged in parallel so as toface each other, and a rotationally driving device for rotating thelight incident faces 7 a to 7 c and the light emission faces 7 d to 7 faround the rotational axial line, and by rotating the rotational prismbody 7 around the rotational axial line R, a light beam which isincident along the optical axis O directing to the rotational axial lineto the light incident faces 7 a to 7 c within a plane which is verticalto the light incident faces 7 a to 7 c, the light emission faces 7 d to7 f and the rotational axial line R is emitted from the confrontinglight emission faces 7 d to 7 f as a light beam parallel to the opticalaxis O, the distance of the light beam from the optical axis varyingwith respect to the time.

According to the beam deflecting device, the rotational prism body 7having two or more pairs of optical faces which are arranged in parallelso as to face each other is used, and a light beam parallel to theoptical axis O, the distance thereof from the optical axis varying withrespect to the time is emitted, so that a long scan width can beachieved without increasing the weight of the rotational prism body 7.

In an apex-angle variable prism device disclosed in JP-A-8-5942, theperipheries of two confronting glass plates 9, 11 are covered by abellows 13, and transparent liquid 14 such as silicon oil or the like isclosely sealed therein. The two confronting glass plates 9, 11 arerelatively inclined and the apex angle between the two glass plates 9,11 is made variable as shown in FIGS. 38A and 38B. In FIG. 38A, the twoglass plates 9 and 11 are kept in parallel, and in this case, theincident angle and the emission angle of a light beam 15 to/from theapex-angle variable prism are equal to each other. On the other hand,when they intersects to each other at an angle as shown in FIG. 38B, thelight beam is bent at some degree as indicated by the light beam 15.

According to the apex-angle variable prism device, when a camera isinclined due to shaking or the like, the angle (apex angle) of theapex-angle variable prism provided in front of a photographing lens iscontrolled so that the light beam 15 corresponding to the inclinationangle is bent, thereby removing blurring.

As shown in FIG. 39, a light deflecting device disclosed inJP-A-11-149050 has a semi-spherical body 17 comprising a plane portionfor refracting/deflecting an incident light beam and a semi-sphericalportion facing the plane portion so that the plane portion is wrapped bythe semi-spherical portion, a support member 19 for supporting thesemi-spherical body 17 so that the semi-spherical body 17 is freelyrotatable and driving members 21, 23 for rotating the semi-sphericalbody 17. The semi-spherical body 17 has a solid body, and is formed of amaterial through which a light beam to be deflected is transmissible. Inaddition, the plane portion and a space or medium 25 which comes intocontact with the plane portion are different in refractive index.

According to this light deflecting device, the light deflection iscarried out mechanically, and thus it is possible to set a largedeflection angle θ in a three-dimensional free direction. Furthermore,arrangements at the incident side and emission side can be achievedalong the transmission direction, and thus the whole device can beminiaturized.

However, the optical switch disclosed in JP-A-2002-23072, the beamdeflecting device disclosed in JP-A-2000-180742 and the apex-anglevariable prism device disclosed in JP-A-8-5942 are unsuitablestructurally or as a driving-mechanism for the construction of theminute transmission type spatial light modulator for carrying out lightdeflection on a pixel basis in an exposure head, a display or the like,and it is difficult to carry out a low-voltage driving operation by anydisclosed driving members even if miniaturization thereof is possible.On the other hand, the light deflecting device disclosed inJP-A-11-149050 is applicable as a minute transmission type spatial lightmodulator. However, since the support portion thereof is filled withlubricant, it is estimated that the response is lowered by the frictionthereof. Furthermore, it has low resistance to shock and temperaturevariation, and thus there is a risk that it has low reliability and ashort lifetime. Under such a condition, it is necessarily andunavoidably difficult to apply this light deflecting device to anexposure head, a display or the like which needs high-speed responsedeflection of μs-order and a semi-permanent operation. Furthermore, anextremely high precision manufacturing technique is required to form ahigh-precision semi-spherical structure which is directly associatedwith the stable performance of the rotational operation of thesemi-spherical body and the recess structure of the surrounding portionwhich is matched with the structure of the semi-spherical body.Therefore, when it is applied to an exposure head, a display or thelike, it is estimated that it is realistically difficult in yield tomanufacture a transmission type spatial light modulation array device inwhich transmission type spatial light modulators each having a largenumber of pixels are arranged. The present invention has beenimplemented in view of the foregoing situation.

SUMMARY OF THE INVENTION

An object of the invention is to provide a transmission type spatiallight modulator and a transmission type spatial light modulation arraydevice that can perform high-speed deflection and a low-voltage drivingoperation, further miniaturize elements and enhance the contrast bysuppressing stray light or unnecessary light. The object can be attainedby adoption of the following constitution.

(1). A transmission type spatial light modulator comprising: a minutetransparent optical member for deflecting and emitting light in adirection different from the incident direction of incident light; asupport member for supporting the minute transparent optical member in amidair position so that a light emission face thereof can be inclinedwith respect to a plane perpendicular to a travel direction of the lightincident direction; and a driving member for obliquely displacing theminute transparent optical member by an electrical mechanical operationto vary the light emission direction from the minute transparent opticalmember.

In the transmission type modulator, the direction and light amount oftransmission light can be controlled by a small displacement amount.Furthermore, emission light is directed in the same travel direction asincident light, and an optical system which is needed in the case of areflection type modulator is not required. In addition, the separationbetween ON light and OFF light can be more easily performed as comparedwith the reflection type modulator. Furthermore, thewavelength-dependence is lowered as compared with an interference typespatial light modulator using the Fabry-Perot effect or the like.

(2). The transmission type spatial light modulator according to (1),further comprising a light shielding member that is disposed ahead ofthe light emission face of the minute transparent optical member andshields any emission light in a direction-variable range of lightemitted from the minute transparent optical member.

In the transmission type spatial light modulator, a desired area in thedirection variable range of light emitted from the minute transparentoptical member can be set to a light transmission area or a lightshielding area.

(3). The transmission type spatial light modulator according to (2),wherein the driving member obliquely displaces the minute transparentoptical member to displace the emission light with respect to the lightshielding member, thereby varying the transmission light amount of theemission light.

In this transmission type spatial light modulator, ON/OFF of lightintensity and a switching operation of a route can be performed incooperation with a light deflecting operation based on the obliquedisplacement of the minute transparent optical member.

(4). The transmission type spatial light modulator according to anyoneof (1) to (3), wherein the minute transparent optical member has arefractive index larger than 1 and light incident and emission faces areformed by non-parallel faces.

In this transmission type spatial light modulator, the minutetransparent optical member can be formed of a structure having a singlerefractive index. The emission angle of the deflected light can befreely set by merely controlling the design of the inclination angles ofthe light incident and emission faces.

(5). The transmission type spatial light modulator according to any oneof (1) to (4), wherein the minute transparent optical member has arefractive index distribution different in refractive index inaccordance with the light travel direction, and a light deflectiondirection based on the refractive index distribution is different fromthe light travel direction.

In this transmission type spatial light modulator, the deflection rangecan be arbitrarily set by using a flat-plate type minute transparentoptical member. Furthermore, the thickness of the minute transparentoptical member can be reduced.

(6). The transmission type spatial light modulator according to any oneof (1) to (4), wherein the minute transparent optical member has a totalreflection face for totally reflecting the incident light.

In this transmission type spatial light modulator, the total reflectionof the incident light is possible in addition to the deflection of theincident light. Accordingly, the deflected light is emitted from theopposite side to the light incident face of the minute transparentoptical member, and the reflected light is emitted from the lightincident face side of the minute transparent optical member, so that theeffective light (ON light) and the unnecessary light (OFF light) areseparated to the opposite sides with respect to the minute transparentoptical member.

(7). The transmission type spatial light modulator according to (6),wherein the minute transparent optical member is obliquely displaced bythe driving member to transmit or totally reflect the incident light.

In this transmission type spatial light modulator, the minutetransparent optical member is obliquely displaced so that the incidentangle of the incident light incident to the total reflection surface issmaller or larger than the critical angle, whereby the ON light and theOFF light are separated to the opposite sides with respect to the minutetransparent optical member. Furthermore, since the total reflection iscarried out by the total reflection surface formed in the minutetransparent optical member, so that internal total reflection (TotalInternal Reflection) can be performed and thus light absorption can bereduced as compared with the reflection on the total reflection surface.

(8). The transmission type spatial light modulator according to (7),further comprising an optical path correcting member that is disposedahead of the light emission face of the minute transparent opticalmember to make an incident angle and an emission angle substantiallycoincident with each other.

In this transmission type spatial light modulator, the emission light(ON light) which is separated to the opposite side to the incident lightwith respect to the minute transparent optical member can straightlytravel in the same direction as the incident light.

(9). The transmission type spatial light modulator according to any oneof (6) to (8), wherein the minute transparent optical member is designedin a prism-shape.

In this transmission type spatial light modulator, a large deflectionangle can be achieved by a small inclination angle. Furthermore, thereflection loss can be reduced, and the light absorption can be reducedas compared with the reflection on the metal surface. Still furthermore,since the deflection angle is large, it is easy to take a margin, andthe degree of freedom of an optical design of an optical path or thelike can be enhanced.

(10). The transmission type spatial light modulator according to (6) to(8), wherein at least a part of the light incident face or lightemission face of the minute transparent optical member is designed in acurved-surface shape.

In this transmission type spatial light modulator, the refractive indexis continuously varied, and the refractive index difference in therefractive index variation range is set to a large value.

(11). The transmission type spatial light modulator according to (1),further comprising: a first prism member for receiving the emissionlight when the minute transparent optical member is obliquely displacedby the driving member and the emission light is emitted from the minutetransparent optical member in a predetermined direction, and emittingthe emission light as effective light while deflecting the emissionlight in a first direction; and a second prism member for receiving theemission light when the minute transparent optical member is obliquelydisplaced by the driving member and the emission light is emitted fromthe minute transparent optical member in a direction different from thepredetermined direction, and deflecting the emission light asunnecessary light in a second direction different from the firstdirection.

In this transmission type spatial light modulator, the emissiondirections of the effective light and the unnecessary light can be madegreatly different by the first prism member and the second prism member,and for example, they can be made to the opposite directions.

(12). The transmission type spatial light modulator according to any oneof (1) to (11), wherein the driving member obliquely displaces theminute transparent optical member by electrostatic force.

In this transmission type spatial light modulator, the minutetransparent optical member can be electrically and mechanically operatedat a high speed and with a low voltage to be obliquely displaced byelectrostatic suction force caused by electrostatically-induced charges.

(13). A transmission type spatial light modulation array devicecomprising transmission type spatial light modulators according toanyone of (1) to (12), the transmission type spatial light modulatorsbeing arranged one-dimensionally or two-dimensionally.

In this transmission type spatial light modulation array device, thetransmission type spatial light modulators having the same structure arearranged one-dimensionally or two-dimensionally, and function as onelight modulation device. Therefore, high-density pixels can be subjectedto light modulation at high speed in an application to an exposure head,a display or the like. Furthermore, the many transmission type spatiallight modulators can be arranged with the same quality and highprecision by a semiconductor manufacturing process.

(14). The transmission type spatial light modulation array deviceaccording to (13), wherein a micro-lens array having a plurality ofmicro-lenses disposed in connection with the respective transmissiontype spatial light modulators is disposed so as to confront the lightincident face.

In this transmission type optical array device, incident light flux isconverged, so that the minute transparent optical member can beminiaturized and reduced in weight. Furthermore, as compared with a casewhere no micro-lens is used, a minute transparent optical member havinga small area can be formed, and thus a driving circuit area can besecured in the comparison of the same substrate area.

According to the transmission type spatial light modulator of thepresent invention, the minute transparent optical member for emittinglight therefrom in a direction different from incident light issupported by the support member so as to be inclined, and the minutetransparent optical member is obliquely displaced by the electricalmechanical operation of the driving member to vary the light emissiondirection. Therefore, the direction of the transmitted light and thelight amount of the transmitted light can be controlled by a smalldisplacement amount, and the high-speed deflection and the low-voltagedriving operation can be implemented. Accordingly, a low powerconsumption driving operation can be performed. Furthermore, in the caseof the reflection type spatial light modulator, the light incident pathand the light reflection path to the modulator exist at the same surfaceside, and thus an optical system for avoiding the interference betweenboth the optical paths is needed. However, according to the transmissiontype spatial light modulator of the present invention, the lightemission light is directed in the travel direction of the incidentlight, so that the optical system needed in the case of the reflectiontype modulator is unnecessary. Accordingly, in the transmission typespatial light modulator of this invention, the construction of theperipheral optical system can be simplified, and thus the spatial lightmodulator can be miniaturized. Furthermore, the separation between theON light and the OFF light can be more easily performed as compared withthe reflection type spatial light modulator, and thus stray light andunnecessary light can be suppressed a and the contrast can be enhanced.Still furthermore, the wavelength-dependence which is observed in aninterference type spatial light modulator using Fabry-Perot effect orthe like can be eliminated.

According to the transmission type spatial light modulation array deviceof the present invention, the transmission type spatial light modulatorsare one-dimensionally or two-dimensionally arranged. Therefore, thetransmission type spatial light modulators having the same structure areone-dimensionally or two-dimensionally arranged on the same substrate,and thus they function as one light modulation device, so thathigh-density pixels can be subjected to light modulation at high speedin an application to an exposure head, a display or the like.Furthermore, many transmission type spatial light modulators can bearranged with the same quality and with high precision by thesemiconductor manufacturing process, so that the light emission lightcan be aligned and image display, etc. can be performed with highquality and high resolution.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a first embodiment of atransmission type spatial light modulator according to the presentinvention.

FIGS. 2A and 2B are cross-sectional views showing (FIG. 2A) an initialstate and (FIG. 2B) an operation state of the transmission type spatiallight modulator shown in FIG. 1.

FIGS. 3A to 3C are diagrams showing the relationship between theinclination angle and the emission angle of the transmission typespatial light modulator shown in FIG. 1.

FIGS. 4A to 4D are diagrams showing the principle of emission anglecontrol based on the oblique displacement of the transmission typespatial light modulator shown in FIG. 1.

FIG. 5 is an enlarged view showing a main part of a minute transparentoptical member shown in FIGS. 4A to 4D.

FIG. 6 is a diagram showing the correlation between the emission angleand the rotational angle in the transmission type spatial lightmodulator (in the case of refractive index n=1.5) shown in FIG. 1.

FIG. 7 is an enlarged view showing a main range of FIG. 6.

FIG. 8 is a diagram showing the correlation between the emission angleand the rotational angle in the transmission type spatial lightmodulator (in the case of the refractive index n=2.03)shown in FIG. 1.

FIG. 9 is an enlarged view showing a main range of FIG. 8.

FIG. 10 is a plan view showing transmission type spatial lightmodulators shown in FIG. 1 which correspond to four pixels.

FIG. 11 is a cross-sectional view taken along XI-XI line of FIG. 10.

FIG. 12 is a cross-sectional view taken along XII-XII line of FIG. 10.

FIGS. 13A and 13B are diagrams showing the operation of the transmissiontype spatial light modulator shown in FIG. 1.

FIGS. 14A to 14H are diagrams showing the manufacturing process of thetransmission type spatial light modulator shown in FIG. 1 in the samecross-sectional view as FIG. 11.

FIGS. 15A to 15H are diagrams showing the manufacturing process of thetransmission type spatial light modulator shown in FIG. 1 in the samecross-sectional view as FIG. 12.

FIG. 16 is an electrode wire diagram showing a second embodiment of thetransmission type spatial light modulator of the present invention.

FIG. 17 is a diagram showing the operation representing a left-sideinclination condition of the transmission type spatial light modulatorshown in FIG. 16.

FIG. 18 is a diagram showing the operation representing a right-sideinclination condition of the transmission type spatial light modulatorshown in FIG. 16.

FIGS. 19A and 19B are cross-sectional views representing a modification1 of the transmission type spatial light modulator shown in FIG. 16 inwhich a minute transparent optical member is displaced by a flexibleflat plate.

FIG. 20 is a perspective view showing a modification 2 of thetransmission type spatial light modulator shown in FIG. 16 which isequipped with a comb-drive.

FIGS. 21A to 21C are cross-sectional views showing a third embodimenthaving a light shielding member.

FIGS. 22A and 22B are cross-sectional views showing a modification ofthe third embodiment in which the position of the light shielding memberis different.

FIGS. 23A and 23B are cross-sectional views showing a fourth embodimentin which the minute transparent optical member has a total reflectionface.

FIGS. 24A and 24B are cross-sectional views showing a modification ofthe fourth embodiment in which the shape of the minute optical member isdifferent.

FIGS. 25A to 25D are cross-sectional views showing a fifth embodimentusing a prism as the minute transparent optical member.

FIG. 26 is a cross-sectional view showing a modification 1 of the fifthembodiment which has an optical path correcting member.

FIG. 27 is a cross-sectional view showing a modification 2 of the fifthembodiment which uses a parallelogram prism.

FIGS. 28A to 28C are cross-sectional views showing a sixth embodiment inwhich the light emission face of the minute transparent optical memberis designed in a curved-surface shape.

FIGS. 29A to 29C are cross-sectional views showing a seventh embodimentin which the minute transparent optical member has a refractive indexdistribution.

FIGS. 30A to 30C are cross-sectional views showing a modification of theseventh embodiment in which the refractive interface is designed in acurved-surface shape.

FIG. 31 is a cross-sectional view of the transmission type spatial lightmodulation array device according to an eighth embodiment which aims atintegration of micro-lenses.

FIG. 32 is a cross-sectional view showing a modification of thetransmission type spatial light modulation array device shown in FIG. 31which is equipped with two-stage micro-lenses.

FIG. 33 is a diagram showing the construction of an exposure deviceaccording to a ninth embodiment using the transmission type spatiallight modulation array device.

FIG. 34 is a block diagram showing the exposure device shown in FIG. 33.

FIG. 35 is a diagram showing the optical path of the exposure deviceshown in FIG. 33.

FIG. 36 is a schematic diagram showing an optical switch serving as aconventional transmission type mechanical light deflector.

FIG. 37 is a diagram showing the construction of a main part of a beamdeflecting device serving as a conventional transmission type mechanicallight deflector.

FIG. 38 is a diagram showing the construction of a main part of anapex-angle variable prism device serving as a conventional transmissiontype mechanical light deflector.

FIG. 39 is a diagram showing the construction of a main part of a lightdeflecting device serving as a conventional transmission type mechanicallight deflector.

Reference numerals are used to identify various elements in the drawingsincluding the following:

-   32 hinge (support member)-   33, 85, 99, 103 minute transparent optical member-   35 driving member-   71 flexible flat plate (support member)-   77 swing shaft (support member)-   83 light shielding member-   89 emission face (total reflection face)-   91, 141 optical path correcting member-   100, 180, 200, 300, 400, 500, 600 transmission type spatial light    modulator-   117 micro-lens array-   117 a micro-lens-   700, 900 transmission type spatial light modulation array device-   L1 incident light-   L2 emission light

DETAILED DESCRIPTION OF THE INVENTION

Preferable embodiments of a transmission type spatial light modulatorand a transmission type spatial light modulation array device accordingto the present invention will be described in detail with reference tothe drawings.

FIG. 1 is a perspective view showing a first embodiment of thetransmission type spatial light modulator according to the presentinvention, and FIGS. 2A to 2B are cross-sectional showing an initialstate (FIG. 2A) and an operation state (FIG. 2B) of the transmissiontype spatial light modulator shown in FIG. 1.

A transmission type spatial light modulator 100 according to anembodiment has a substrate 31, a minute transparent optical member 33mounted on the substrate 31, a hinge (support member) 32 for supportingthe minute transparent optical member 33 at both the side portionsthereof, and a driving member 35 for obliquely displacing the minutetransparent optical member 33 as basic constituent elements as shown inFIG. 1 and FIGS. 2A and 2B.

The minute transparent optical member 33 works to deflect light in adirection different from an incident direction of incident light L1. Theminute transparent optical member 33 comprises movable film 37 having anelectrically conductive portion described later formed at at least apart thereof, and a deflecting portion 39 provided on the upper surfaceof the thin film portion 37. The deflecting portion 39 may be a minuteprism formed of glass, for example. The movable film 37 and thedeflecting portion 39 may be formed separately from each other orintegrally with each other.

The hinge 32 supports the minute transparent optical member 33 so thatthe movable film 37 is spaced from the substrate 31 through a gap 51 inparallel to the substrate 31 as shown in FIG. 2A, and also supports theminute transparent optical member 33 at a midair position so that thelight emission face (the upper surface of the deflecting portion 39) isfurther inclined with respect to a plane perpendicular to the traveldirection of incident light (that is, the surface of the substrate 31)as shown in FIG. 2B when force is applied in a distortion direction by adriving member 35.

The transmission type spatial light modulator 100 is designed, forexample, so that the pixel area is set to 20 μm×20 μm in size, themovable film 37 is set to 10 μm×5 μm in size and the height of the shortside of the deflecting portion 39 is set to about 3 to 4 μn.

The driving member 35 obliquely displaces the minute transparent opticalmember 33 by an electrical mechanical operation to greatly vary theemission direction of light from the minute transparent optical member33 as shown in FIG. 2B. The driving member 35 has an electricallyconductive portion provided to the movable film 37 (a voltage Vm isapplied to the electrically conductive portion, and even in theconstruction that the electrically conductive portion is added to themovable film 37, the movable film 37 itself may be formed ofelectrically conductive film), and lower electrodes 53, 54 which aredisposed at the substrate 31 side and confront the movable film 37through the above gap 51. The lower electrodes 53, 54 are arranged atboth the sides between which the hinge 32 is sandwiched, and voltages V1and V2 are applied to the lower electrodes 53, 54, respectively.

Any material such as a glass substrate or the like may be used as thesubstrate 31 in so far as it is transparent to incident light. Even whenit is an opaque substrate such as a Si substrate or the like, it isusable by providing a light transmissible property to only an area whereincident light is deflected. Specifically, it is preferable thatcircuits (normally, a CMOS circuit and a wiring circuit therefor) fordriving a device is formed on the Si substrate, the upper surfacethereof is flattened by an insulating layer and an opening hole isformed at the area where the light deflection is carried out. Themovable film 37 and the lower electrodes 53, 54 are provided on theupper surface of the flattened insulating layer, and these areelectrically connected to one another through contact holes (not shown)provided in the insulating layer. These structures will be described indetail later.

FIGS. 3A to 3B are diagrams showing the relationship between theinclination angle and the emission angle of the transmission typespatial light modulator shown in FIG. 1. In the transmission typespatial light modulator 100, for example when the prism angle (theintersecting angle between the incident face and the emission face) θoof a triangular deflecting portion 39 having a refractive index n=1.5 isequal to 30°, the inclination angle θr=0° and the emission angle θe ofthe deflected light is slightly less than 20° under an initial statewhere the driving member 35 is not actuated as shown in FIG. 3B.Furthermore, as shown in FIG. 3A, when the driving member 35 is actuatedand the inclination angle θr=−15°, the incident angle of the incidentlight to the emission face is increased, and thus the emission angle θeof the deflected light emitted from the emission face is greatly variedto 30°. In this specification, the clockwise rotation is set as apositive-direction rotation, and the counterclockwise rotation is set asa negative-direction rotation and thus it is added with a minus sign.Furthermore, as shown in FIG. 3C, even when the driving member 35 isactuated and the inclination angle θr=15°, the emission angle θe of thedeflected light is equal to slightly less than 15°, and the emissionangle θe is not so different angle from that under the state of FIG. 3A.In the figures, 57 represents a transparent front-surface protectionsubstrate disposed at the opposite side to the substrate 31 through theminute transparent optical member 33 so as to confront the substrate 31.

FIGS. 4A to 4D are diagrams showing the principle of emission anglecontrol on the basis of inclination displacement of the transmissiontype spatial light modulator shown in FIG. 1, and FIG. 5 is an enlargedview showing the main part of the minute transparent optical membershown in FIG. 1. At least the deflecting portion 39 of the minutetransparent optical member 33 has a refractive index n larger than 1,and the light incident face and the light emission face are formed ofnon-parallel faces. The minute transparent optical member 33 is formedof a structure having a single refractive index, whereby the spatiallight modulator can be easily formed. Furthermore, the emission angle ofthe deflected light can be freely set by merely controlling the designof the inclination angle (prism angle) of the light incident face andthe light emission face, and the spatial light modulator having adesired deflection angle can be easily manufactured.

When the minute transparent optical member 33 is rotated in the positivedirection (clockwise direction) from the initial state that theinclination angle θr shown in FIG. 4B is equal to zero, the transmissiontype spatial light modulator 100 is set to a state shown in FIG. 4A, andincident light is incident to the emission face substantiallyvertically, so that the deflection angle difference is small. On theother hand, when it is rotated in the negative direction(counterclockwise direction), the transmission type spatial lightmodulator 100 is set to a state shown in FIG. 4C, the emission angle ofthe deflected light is greatly varied, and when the inclination angle θris larger than the critical angle θcc, the transmission type spatiallight modulator 100 is set to a state shown in FIG. 4D, so that theincident light L1 is totally reflected by the emission face, and thus isnot emitted from the emission face.

The emission angle θe of the deflected light can be controlled by usingthe prism angle θo, the inclination angle θr and the refractive index nas parameters. That is, these values and the emission angle θe areassociated with each other as shown in FIG. 5. That is,

$\begin{matrix}{{\theta\; a} = {\arcsin( {\sin\;\theta\;{r/n}} )}} \\{{\theta\; b} = {{\theta\; r} - {\theta\; a}}} \\{{\theta\; c} = {{\pi/2} - {\theta\; b} - ( {{\pi/2} - {\theta\; o} - {\theta\; r}} )}} \\{= {{\theta\; o} + {\theta\; r} - {\theta\; b}}} \\{= {{\theta\; o} + {\theta\; a}}} \\{{\theta\; d} = {\arcsin( {n\;\sin\;\theta\; c} )}}\end{matrix}$

Accordingly, the emission angle θe is represented as follows:

$\begin{matrix}{{\theta\; e} = {{\theta\; d} - ( {{\theta\; b} + {\theta\; c}} )}} \\{= {{\theta\; d} - ( {{\theta\; o} + {\theta\; r}} )}} \\{= {{\arcsin( {n\;\sin\;\theta\; c} )} - ( {{\theta\; o} + {\theta\; r}} )}} \\{= {{\arcsin( {n\;\sin\;( {{\theta\; o} + {\theta\; a}} )} )} - ( {{\theta\; o} + {\theta\; r}} )}} \\{= {{\arcsin\lbrack {n\;\sin\{ {{\theta\; o} + {\arcsin( {\sin\;\theta\;{r/n}} )}} \}} \rbrack} - ( {{\theta\; o} + {\theta\; r}} )}}\end{matrix}$

FIG. 6 is a diagram showing the correlation between the emission angleθe and the rotational angle (inclination angle) θr based on the abovecalculation equations every prism angle θo=10° in the case of therefractive index n=1.5, and FIG. 7 is an enlarged view of the main partrange of FIG. 6. FIG. 8 is a diagram showing the correlation between theemission angle θe and the rotational angle (inclination angle) θr everyprism angle θo=100 in the case of the refractive index n=2.03, and FIG.9 is an enlarged view of the main part range of FIG. 8.

In order to drive the transmission type spatial light modulator 100 athigh speed, it is more advantageous to set the inclination angle θr to avalue which is as small as possible. Therefore, the inclination angle θr=±15° is set to the upper limit of the driving range, and the prismangle θo is set to 30°, whereby 30° can be secured as the emission angleθo in the case of the refractive index n=1.5 (FIG. 6, FIG. 7). That is,the deflected light of the emission angle 30° is set as ON light (or OFFlight), and the deflected light of the emission angle of 15° to 20° (seeFIGS. 3B and 3C) is set to OFF light (or ON light), whereby the ON lightand the OFF light can be easily discriminated from each other.

A higher advantage could be achieved by forming the transmission typespatial light modulator 100 of a material having a high refractiveindex. FIGS. 8 and 9 show an example of the refractive index n=2.03, andas compared with FIGS. 6 and 7, it is sufficient to set the prism angleθo to 20° in order to secure the same emission angle θe =30°, so thatthe deflecting portion 39 ca be easily manufactured. As compared withFIGS. 6 and 7, when the deflecting portion 39 having the same prismangle is used, the driving range of the inclination angle can be furthernarrowed, and the higher speed driving can be performed. Furthermore, bysecuring a larger emission angle θe, the discrimination between the ONlight and the OFF light can be further easily performed.

The following materials are used as the material having a highrefractive index.

Al₂O₃: n=1.67

SiN_(x): n=2.03

TiO₂: n=2.28

DLC: n=2.4

Ta₂O₅: n=2.14

ITO: n=2.00

FIGS. 8 and 9 show the example of SiN_(x) having the refractive indexn=2.03. SiN_(x), is transparent over the range from the ultraviolet areato the infrared area and suitable for the semiconductor process, andalso the stress control of the structure can be performed. Therefore, itis suitably used as the transmission type spatial light modulator 100,so that it makes easy to manufacture a deflecting portion 39 having aprism angle θo of 25 to 30° and a rotational angle θr=±(5 to 15°).

When the prism angle θo is equal to 30°, the practical shape of thedeflecting portion 39 may be designed so that light is totally reflectedat the prism emission interface for the rotational angle θr=+0° or more,and light is transmitted at an emission angle θe=+40° and at therotational angle θr=−5°. This shape will be described with respect toanother embodiment described later.

FIG. 10 is a plan view showing transmission type light modulators 100 offour pixels which are manufactured on a semiconductor substrate, FIG. 11is a cross-sectional view taken along XI-XI line of FIG. 10 and FIG. 12is a cross-sectional view taken along XII-XII line of FIG. 10.

A first insulating layer 151 of SiO₂ or the like is formed on atransparent substrate 150 of glass, quartz or the like, a drivingcircuit 152 based on a CMOS circuit is formed on the first insulatinglayer 151 by an Si semiconductor process, and a second insulating layer153 of SiO₂ or the like is formed on the driving circuit 152. Thedriving circuit 152 is provided so that it is avoided from beingprovided just below the deflecting portion 39 comprising the transparentstructure.

Metal film of aluminum or the like is laminated on the second insulatinglayer 153, and the metal film is subjected to patterning, so that thelower electrodes 53, 54 are provided every pixel. Furthermore, stopperfilm 58 is also formed from the metal film, and the end portion of themovable film 37 abuts against the stopper film 58 when the movable film37 is inclined. The lower electrodes 53, 54 are connected to the drivingcircuit 152 through contact holes 53 a, 54 a provided in the secondinsulating layer 153, respectively.

Electrically conductive film is formed above the lower electrodes 53, 54through a gap 51, and the electrically conductive film thus formed issubjected to patterning so that the movable film 37 of each pixel,hinges 32 linked to the movable film 37 and support portions 155 forsupporting the movable film 37 through the hinges 32 on the transparentsubstrate 150. A method of forming the electrically conductive film willbe described later. A through hole 56 is formed at the center portion ofthe movable film 37 of each pixel, and the deflecting portion 39 formedof the transparent structure is formed above the through hole 56.

The above structure is formed so that one deflecting portion 39 isprovided every pixel, and these pixels are arranged one-dimensionally ortwo-dimensionally on the substrate, thereby constituting an spatiallight modulation array. It is practically preferable that a one-pixelarea is equal to 10 μm to 100 μm in square, and the opening portion(through hole 56) is equal to 4 μm to 80 μm in square, however, they arenot limited to these sizes.

FIGS. 13A and 13B are diagrams showing the operation of the transmissiontype light modulator 100. When a potential difference is applied to thelower electrodes 53, 54 with respect to the movable film 37,electrostatic force occurs in the movable film 37, and a rotationaltorque works around the hinge 32. Accordingly, by controlling thepotentials V1, V2 of the respective electrodes 53, 54, the movable film37 can be obliquely displaced to the right and left sides. At this time,the deflecting portion 39 is formed integrally with the movable film 37,and thus the deflecting portion 39 is obliquely displaced in conformitywith the oblique displacement of the movable film 37. The inclinationangles of the movable film 37 and the deflecting portion 39 aredetermined by the electrostatic force acting on each movable film 37 andthe elastic force of the hinge 32.

The output of the driving circuit 152 which can be independentlycontrolled every pixel is connected to the lower electrodes 53, 54provided every pixel, and the potentials V1, V2 are applied to the lowerelectrodes 53, 54. The movable film 37 is electrically connected to thestopper film 58 on the substrate 150 through the hinge 32 and thesupport portion 155, and a potential Vm is applied to the movable film37. The supply of the potentials V1, V2 is controlled by the drivingcircuit 152, and for example 0V or 5V digital potential is suppliedaccording to an image signal. In order to obliquely control the movablefilm 37 at a higher speed, it is preferable to carry out low-voltagedigital driving of 0V or 3V.

The potential Vm may be controlled to be supplied from the drivingcircuit 152 provided every pixel or every plural pixels, or it may becontrolled to be supplied from a common driving circuit of the wholearray device. Furthermore, it may be controlled to be supplied from acircuit at the outside of the array device. The potential Vm ispreferably controlled by analog potential. Here, when the absolute valueof the potential difference between the movable film 37 and theelectrode 53, 54 is represented by V(1), V(2), the relationship with thecontrol potential is represented as follows:V(1)=|Vm-V1|V(2)=|Vm-V2|

For V(1)=V(2)=0, external force occurring in the movable film 37 isequal to zero, and the state when the device has been formed is kept.That is, the movable film 37 and the deflecting portion 39 aresubstantially horizontal to the substrate 150. This state is stabilizedby the elastic force of the hinge 32.

For V(1)=V(2)≠0, the electrostatic force occurring in the movable film37 is also symmetrical with respect to the hinge 32; Therefore, thestate at the formation time of the device is kept, and the movable film37 and the deflecting portion 39 are substantially horizontal to thesubstrate 150.

When at least one of V(1) and V(2) is not equal to zero and also theyare different from each other, the electrostatic force occurring in themovable film 37 is asymmetrical with respect to the hinge 32.Accordingly, the movable film 37 and the deflecting portion 39 areobliquely displaced with respect to the substrate 150. For example, inthe case of V(1)>V(2), the electrostatic force acting between theelectrode 53 and the left side of the movable film 37 is larger than theelectrostatic force acting between the electrode 54 and the right sideof the movable film 37 as shown in FIG. 13( a), and the movable film 37is inclined to the left side. That is, it is rotated in thecounterclockwise direction. Conversely, in the case of V(1)<V(2), theelectrostatic force acting between the electrode 54 and the right sideof the movable film 37 is larger than the electrostatic force actingbetween the electrode 53 and the left side of the movable film 37 asshown in FIG. 13( b), and thus the movable film 37 is inclined to theright side. That is, it is rotated in the clockwise direction.Accordingly, by properly controlling V(1) and V(2), the inclinationangle θr of the movable film 37, that is, the deflecting portion 39 canbe freely controlled.

When V(1) or V(2) is sufficiently high and the electrostatic forcecontributing to the oblique displacement is larger than the elasticforce of the hinge 32 or the electrostatic force occurring in theopposite direction, the movable film 37 and the deflecting portion 39are obliquely displaced so that the end portion of the movable film 37comes into contact with the stopper film 58. Accordingly, theinclination angle at this time is geometrically determined by the lengthof the movable film 37 from the center portion of the hinge and the gapdistance till the substrate. By properly selecting these shapes, adesired inclination angle can be freely designed. Here, even when theend portion of the movable film 37 comes into contact with the stopperfilm 58, no short-circuit current flows because they are set to the samepotential.

The present invention is not limited to the device construction, theelectrode construction and the driving method of the above embodiment,and any construction may be adopted insofar as it is conformed with thesubject matter of the present invention. For example, the device may bedesigned so that the inclination is carried out not by the vibration ofthe hinge, but by slack of a rib on which the end portion is supported.Furthermore, a driving electrode may be provided above the movable film37 to intensify the electrostatic force (an embodiment having thisconstruction will be described later). Furthermore, the movable film 37may be driven in non-contact with the substrate 150 without providingany stopper film 58.

FIGS. 14A to 14H and FIGS. 15A to 15H are diagrams showing themanufacturing process of the transmission type spatial light modulatorshown in FIGS. 10 to 12. FIGS. 14A to 14H show the manufacturing processin the same cross-sectional view as FIG. 11, and FIGS. 15A to 15H showthe manufacturing process in the same cross-sectional view as FIG. 12.FIGS. 14A and 15A are cross-sectional views showing the samemanufacturing process. The same is applied to B to H.

First, as shown in FIG. 14A and FIG. 15A, the first insulating layer151, the driving circuit 152 formed of CMOS and the second insulatinglayer 153 are formed and laminated, the electrically conductive film isformed on the second insulating layer 153 and the stopper film 58 andthe electrodes 53, 54 are patterned from the electrically conductivefilm.

In order to form the driving circuit 152 of CMOS on the transparentsubstrate 150, the following method is used. First, the driving circuit152 of CMOS is formed on an SOI (Si on Insulator) substrate by an Sisemiconductor process, and then the Si substrate is exfoliated from theinsulating layer 15 below the driving circuit 152. The driving circuit152 and the insulating later 151 thus exfoliated are substituted onto atransparent substrate 150 by a transfer method or the like.Alternatively, the first insulating layer 151 is formed on thetransparent substrate 150, and then TFT (Thin Film Transistor) isdirectly formed to form the driving circuit 152.

SiO₂ is formed on the driving circuit 152 thus formed by PECVD to formthe second insulating layer 153. The contact holes 53 a, 54 a forconnecting the output of the driving circuit 152 to each of theelectrodes 53, 54 are formed by a patterning treatment usingphotolithography and fluorine-based RIE etching. TiN thin film is formedas base film by sputtering (not shown), and subsequently tungsten (W) isformed by sputtering, whereby tungsten is embedded in the contact holes53 a, 54 a.

Furthermore, the surface thereof is flattened to form the flat secondinsulating layer 153 having the contact holes 53 a, 54 a embedded withtungsten. Al serving as the electrically conductive film (preferably Alalloy containing metal having high melting point) is formed on thesecond insulating layer 153 by sputtering, and patterned into a desiredelectrode shape by photolithography and chlorine-based RIE etching,thereby forming the driving electrodes 53, 54 and the stopper film 58.At this time, the driving electrodes 53, 54 are connected to the outputof the driving circuit 152 through the contact holes 53 a, 54 a.

Subsequently, as shown in FIG. 14B and FIG. 15B, positive type resistfilm 156 is coated on the surface, and a portion thereof which willserve as the support portion 155 of the hinge 32 is patterned byphotolithography and then subjected to hard-baking. The hard-baking iscarried out at a temperature higher than 200° C. while DeepUV isirradiated. Accordingly, the shape thereof is kept even in thesubsequent high-temperature process, and it is insoluble by resistexfoliating solvent. By coating and forming resist film, the resistsurface is flattened irrespective of any step of the base film. Theresist layer functions as a sacrifice layer, and is removed in thesubsequent process. Accordingly, the film thickness of the resist afterthe hard-baking determines the gap 51 (see FIG. 2A) between the futurelower electrodes 53, 54 and the hinge 32 (and the movable film 37).

Subsequently, as shown in FIG. 14C and FIG. 15C, electrically conductivefilm 157 of Al (preferably, Al alloy containing metal having a highmelting point) is formed by sputtering, and only an opening portion(through hole 56 of FIG. 1 and FIG. 10) is patterned into a desiredshape by photolithography and chlorine-based RIE etching.

Subsequently, as shown in FIG. 14D and FIG. 15D, a transparent insulatorformed of siO₂ which will serve as the deflecting portion 39 is formedby PECVD, and subjected to a patterning so as to cover the periphery ofthe opening portion 56 by photolithography and fluorine-based RIEetching.

Subsequently, as shown in FIG. 14E and FIG. 15E, positive type resistfilm 159 is coated, and a resist structure 159 having the same shape asthe deflecting portion 39 having a desired shape (a right triangularprism shape in the example of the figures) is formed on the transparentinsulator 158 on the opening portion 56 by photolithography based on agray-scale photomask.

Subsequently, as shown in FIG. 14F and FIG. 15F, the transparentinsulator 158 is formed to have the same shape as the deflecting portion39 by fluorine-based RIE etching. That is, the shape of the resiststructure 159 is transferred to the transparent insulator 158 to therebyforming the deflecting portion 39.

Subsequently, as shown in FIG. 14G and FIG. 15G, the electricallyconductive film 157 is patterned by photolithography and chlorine-basedRIE etching to form the hinge 32, the support portion 155 and themovable film 37 from the electrically conductive film 157.

Finally, as shown in FIG. 14H and FIG. 15H, the resist layer 156 servingas the sacrifice layer is removed by oxygen-based plasma etching(ashing) to form the gap 51, thereby forming an spatial light modulatorhaving a desired structure.

FIG. 16 is a diagram showing a transmission type spatial light modulator180 according to a second embodiment of the present invention. Thetransmission type spatial light modulator 180 of the second embodimentis different from the transmission type spatial light modulator 100 onin the construction of the driving member. FIG. 17 shows a left-sideinclination state (counterclockwise rotation state) of the transmissiontype spatial light modulator, and FIG. 18 shows a right-side inclinationstate (clockwise rotation state) of the transmission type spatial lightmodulator 180.

In the first embodiment, only the lower electrodes 53, 54 are providedas the driving member 35. However, in this embodiment, in addition tothe lower electrodes 53, 54, upper electrodes 61 and 62 are disposed atboth the sides of the hinge 32 (not shown) so as to sandwich the movablefilm 37 therebetween. In the example shown in FIG. 16, electricallyconductive film 59 is formed on the whole lower surface of the movablefilm 37 because the movable film 37 is formed of insulating film,however, the movable film 37 itself may be formed of electricallyconductive film as in the case of the first embodiment.

That is, in the transmission type spatial light modulator 180 of thisembodiment, two lower electrodes 53, 54 are arranged around a hinge atthe lower side of the movable film 37 constituting a minute transparentoptical member 33, and also two upper electrodes 61, 62 are arrangedaround a hinge at the upper side of the movable film 37. That is, thetorsion center of the hinge is located at the cross point between a pairof diagonal lines connecting diagonal electrodes (the lower electrodes53, 54, the upper electrodes 61, 62) arranged at the four sides of upperand lower and right and left sides. Accordingly, the electrostatic forceis effectively applied to the movable film 37 around the torsion centeraxis. The minute transparent optical member 33 can be actively driven tobe clockwise rotated and counterclockwise rotated by the electrostaticforce based on the electrodes arranged at the upper and lower sides.

As the basic operation, the transmission type spatial light modulator180 swings and displaces the minute transparent optical member 33 byapplying voltages to the lower electrodes 53, 54, the upper electrodes61, 62 and the electrically conductive film 59.

In the transmission type spatial light modulator 180, when a potentialdifference is applied to the first lower electrode 5, the second lowerelectrode 54, the first upper electrode 61 and the second upperelectrode 62 with respect to the electrically conductive film 59,electrostatic force occurs between each electrode and the electricallyconductive film 59, and a rotational torque works around the torsioncenter axis of the hinge. Accordingly, by controlling the potentials ofthe respective electrodes, the deflecting portion 39 can be rotationallydisplaced clockwise or counterclockwise.

For example, as shown in FIG. 16, the potential V1 is applied to thefirst lower electrode 53, the second upper electrode 62, and thepotential V2 is applied to the second lower electrode 54 and the firstupper electrode 61, and the potential Vm is applied to the electricallyconductive film 59.

Here, the potential difference of V1 from Vm is represented by V(1) andthe potential difference of V2 from Vm is represented by V(2). ForV(1)=V(2)=0, the external force occurring in the minute transparentoptical member 33 is equal to zero, the state at the time when thedevice is formed is kept, and the minute transparent optical member 33is substantially horizontal to the substrate 31 as shown in FIG. 8. Thisstate is stabilized by the elastic force of the hinge.

For V(1)=V(2)≠0, the electrostatic force occurring in the minutetransparent optical member 33 is symmetrical with respect to the torsioncenter of the hinge, the state at the time when the device is formed isalso kept, and the minute transparent optical member 33 is substantiallyhorizontal to the substrate 31.

When at least one of V(1) and V(2) is equal to zero and they aredifferent from each other, the electrostatic force occurring in theminute transparent optical member 33 is asymmetrical with respect to thetorsion center axis of the hinge, and the minute transparent opticalmember 33 is inclined with respect to the substrate 31.

For example, for V(1)>V(2), the electrostatic force F generated by thefirst lower electrode 53 and the second upper electrode 62 is largerthan the electrostatic force f generated by the second lower electrode54 and the first upper electrode 61, and the minute transparent opticalmember 33 is inclined to the left side as shown in FIG. 17. Converselyfor V(1)-<V(2), the electrostatic force F generated by the second lowerelectrode 54 and the first upper electrode 61 is larger than theelectrostatic force f generated by the first lower electrode 53 and thesecond upper electrode 62, and the minute transparent optical member 33is inclined to the right side.

At this time, in a case where V(1) and V(2) are sufficiently large, theminute transparent optical member 33 can be easily rotationallydisplaced in any direction from the flat state even when the differencebetween V(1) and V(2) is small. This means that when the potential to becontrolled is set to V1 and V2, the potential difference therebetweenmay be small. Therefore, the voltage of the control circuit can bereduced, and there is an advantage in cost performance and integrationperformance.

By properly supplying the potentials to V1, V2, Vm, the minutetransparent optical member 33 can be displaced to any position, forexample, in a clockwise direction, in a counterclockwise direction andin a flat direction by the electrostatic force occurring in eachelectrode and the elastic force of the hinge. Furthermore, the drivingmethod at this time may be based on analog control (control for anydisplacement) or digital control (control for binary displacement).

With respect to the rotational driving operation described above, aproper rotation stopper (for example, the stopper film 58 of the firstembodiment) is provided, and the minute transparent optical member 33 isrotationally displaced until it comes into contact with the stopper,whereby the rotational angle can be controlled with high precision.Furthermore, by using the linear area of the voltage-displacementcharacteristic, the minute transparent optical member 33 can berotationally displaced so that the minute transparent optical member 33does not come into contact with the stopper. In this case, there is nocontact portion, and thus there occurs no problem such as attachment orthe like, and the reliability can be enhanced. The electrode wiring andthe displacing operation method of the minute transparent optical member33 based on each potential control are embodiments, and thus the presentinvention is not limited to these embodiments.

In the transmission type spatial light modulator 180, the driving member35 obliquely displaces the minute transparent optical member 33 with theelectrostatic force as described above, and thus the high-speed driving,the low-voltage driving and the low power-consumption driving can beperformed.

Accordingly, according to the transmission type spatial light modulator180, the minute transparent optical member 33 for emitting light in adirection different from the incident light L1 is supported by thesupport member so that it can be inclined, and the minute transparentoptical member 33 is obliquely displaced by the electrical mechanicaloperation of the driving member 35 to thereby vary the light emissiondirection, so that the direction of the transmitted light and the lightamount thereof can be controlled by a small displacement amount, and thehigh-speed deflection and the low-voltage driving can be implemented.Furthermore, in the case of the reflection type modulator, the lightincident path and the light reflection path with respect to the deviceexist at the same surface side, and thus an optical system is requiredto avoid the interference between both the paths. However, according tothe transmission type spatial light modulator 180 of this embodiment,the emission light is directed to the travel direction of the incidentlight and thus an optical system which is required in the case of thereflection type modulator is not required, and the construction of theperipheral optical system is simplified, so that the modulator can beminiaturized. Furthermore, as compared with the reflection typemodulator, the effective light (ON light) and the unnecessary light (OFFlight) can be more easily separated from each other, so that the straylight and the unnecessary light can be suppressed, and the contrast canbe enhanced. Furthermore, there can be eliminated thewavelength-dependence which is observed in the interference type spatiallight modulator using the Fabry-Perot effect or the like.

FIGS. 19A and 19B are cross-sectional views showing a modification 1 ofthe transmission type spatial light modulator according to the secondembodiment in which a flexible flat plate is bent to displace a minutetransparent optical member, and FIG. 20 is a perspective view showing amodification 2 of the transmission type spatial light modulator which isequipped with a comb-drive.

The transmission type spatial light modulator 181 can adopts a structureshown in FIG. 19A to drive the minute transparent optical member 33, forexample. This driving structure has a minute transparent optical member33 (comprising the movable film 37 and the deflecting portion 39) fordeflecting the incident light L1, at least one flexible flat plate 71which is pivotably connected to the minute transparent optical member 33at one end thereof and freely movably connected to the support portion67 at the other end thereof, fixed electrodes 53, 54, 61, 62 fordisplacing the minute transparent optical member 33, and a movableelectrode 75 provided on the flexible flat plate 71. The fixedelectrodes 53, 54, 61, 62 are disposed so as to confront the upper andlower portions of the flexible flat plate 71 through gaps, and fixed tothe substrate 31. The flexible flat plate 71 is driven by theelectrostatic force acting between the fixed electrodes 53, 54, 61, 62and the movable electrode 75, thereby obliquely displacing the minutetransparent optical member 33.

In this transmission type spatial light modulator 181, when a voltage isapplied between the fixed electrode 53, 54, 61, 62 and the movableelectrode 75 which connects the minute transparent optical member 33 andthe support portion 67 and is provided on the minute transparent opticalmember 33, electrostatic force is generated between the fixed electrode53, 54, 61, 62 and the movable electrode 75. The minute transparentoptical member 33 is attracted to the substrate 31 (in an upwarddirection or downward direction), and as a result, the minutetransparent optical member 33 is obliquely displaced as shown in FIG.19B. In order to return the minute transparent optical member 33 to thestate of FIG. 19A, the voltage between the movable electrode 75 and thefixed electrode 53, . . . is set to zero.

Furthermore, the transmission type spatial light modulator may adopt astructure as shown in FIG. 20 to drive the minute transparent opticalmember 33. In the driving structure of the transmission type spatiallight modulator 182, the minute transparent optical member 33 is fixedat the center portion of the support member (hinge) 77, and supportshafts 79, 79 are fixed to both the ends of a swing shaft 77 so as to beperpendicular to the swing shaft 77. A so-called comb-drive 81 servingas the driving member is provided to each of the end portions of thesupport shafts 79, 79. In the comb-drive 81, a comb-shaped upperelectrode plate 81 a and a comb-shaped lower electrode 81 b are orientedso that the teeth thereof are mutually engaged with one another, andboth the ends of the support shafts 79, 79 are vertically moved by theelectrostatic force acting between these confronting electrodes, so thatthe swing shaft 77 is rotated and the minute transparent optical member33 can be freely rotated in both the clockwise and counterclockwisedirections.

Next, a third embodiment of the transmission type spatial lightmodulator according to the present invention will be described. FIGS.21A to 21C are cross-sectional views showing the third embodiment havinga light shielding member, and FIGS. 22A and 22B are cross-sectionalviews showing a modification of the third embodiment in which theposition of the light shielding member is different. In the followingembodiments and modifications, the same members as shown in FIGS. 1 to20 are represented by the same reference numerals, and the duplicativedescription thereof is omitted.

A transmission type spatial light modulator 200 of this embodiment haslight shielding member 83 in front of the light emission face of theminute transparent optical member 33. The light shielding member 83 maybe light shielding film formed on the front-surface protection substrate57, for example. The light shielding member 83 shields some emissionlight in a direction-variable range of light emitted from the minutetransparent optical member 33. The light shielding is carried out-byabsorption or reflection.

In the transmission type spatial light modulator 200, for example whenthe prism angle θo of the deflecting portion 39 having a refractiveindex n=1.5 is formed as shown in FIG. 21B, the inclination angle θr isequal to 0° and the emission angle θe of the deflected light is slightlyless than 20° under an initial state where the driving member 35 is notactuated. At this time, the emission light L2 is shielded by the lightshielding member 83. Furthermore, the emission angle θe of the deflectedlight is equal to 15° even when the driving member 35 is actuated andthe inclination angle θr is equal to 15° as shown in FIG. 21A, and thusthe emission light L2 is shielded by the light shielding member 35. Onthe other hand, when the driving member 35 is actuated and theinclination angle θr is equal to −15° as shown in FIG. 21C, the emissionangle θe of the deflected light is greatly varied to 30°, so that theemission light L2 is out of the light shielding member 83 and thusemitted from the front-surface protection substrate 57.

Furthermore, as shown in FIGS. 22A and 22B, the light shielding member83 may be provided at the opposite side to that in the case of FIGS. 21Ato 21C. In this case, as shown in FIG. 22A, the emission light L2 isshifted out of the light shielding member 83 and made to be emitted fromthe front-surface protection substrate 57 under the initial state wherethe driving member 35 is not actuated. Furthermore, as shown in FIG.22B, when the driving member 35 is actuated and light emitted from theemission face of the minute transparent optical member 33 is greatlydeflected, the emission light L2 is shielded by the light shieldingmember 83.

According to the transmission type spatial light modulator 200, there isprovided the light shielding member 83 for shielding some emission lightemission light in the direction-variable range of the light emitted fromthe minute transparent optical member 33. Accordingly, a desired area inthe direction-variable range of light emitted from the minutetransparent optical member 33 can be set as a light transmissible areaor light shielding area. Furthermore, the driving member 35 obliquelydisplaces the minute transparent optical member 33 to displace theemission light with respect to the light shielding member 83, therebyvarying the light amount of transmission light. Therefore, the drivingmember is made to function as an optical switch which enables ON/OFF oflight intensity or switching of a route in cooperation with the lightdeflecting operation based on the oblique displacement of the minutetransparent optical member 33.

Next, a fourth embodiment of the transmission type spatial lightmodulator according to the present invention will be described. FIGS.23A and 23B are cross-sectional views showing the fourth embodiment inwhich the minute transparent optical member is obliquely driven to emitincident light from the emission face thereof or totally reflect theincident light from the emission face, and FIGS. 24A and 24B arecross-sectional views showing a modification of the fourth embodiment inwhich the shape of the minute transparent optical member is different.

The transmission type spatial light modulator 300 according to thisembodiment is designed so that the emission face 89 of the deflectingportion 87 is swung in the vicinity of the critical angle with respectto the incident light L1. That is, the deflecting portion 87 of thisembodiment is formed at the prism angle θo=45°. For example, in the caseof glass having a refractive index n=1.5, the total reflection criticalangle θcc is equal to about 42°, and the distance p from the prismcorner portion to the apex angle portion is set to about 5 μm.

In the transmission type spatial light modulator 300, an optical pathcorrecting member 91 for making the incident angle and the emissionangle substantially coincident with each other may be provided in frontof the light emission face of the minute transparent optical member 85.A prism is suitably used as the optical path correcting member 91.

In the transmission spatial light modulator 300, under the initial statewhere the driving member 35 is not actuated, the inclination angleθr=0°, and thus the incident light L1 is incident to the emission face89 at an angle of 45° larger than the critical angle of 42° as shown inFIG. 23A. Accordingly, the incident light L1 is totally reflected fromthe emission face 89, and thus no light is emitted from the emissionface 89 to the optical path correcting member 91. On the other hand,when the driving member 35 is actuated, as shown in FIG. 23B, theincident angle of the incident light L1 to the emission face 89 issmaller than the critical angle, the emission light L2 passes throughthe emission face 89 while being bent, further passes through theoptical path correcting member 91 and then is emitted in parallel to theincident light L1 (normally-off control).

According to the transmission type spatial light modulator 300, theemission face 89 of the minute transparent optical member 85 is providedin the vicinity of the angle at which the incident light L1 is totallyreflected, and also not only the deflection of the incident light L1,but also the total reflection of the incident light L1 can be performed.Accordingly, the deflected light is emitted from the opposite side tothe light incident face of the minute transparent optical member 85, andalso the reflected light is emitted from the light incident face side ofthe minute transparent optical member 85, so that the effective light(ON light) and the unnecessary light (OFF light) can be separated to theopposite sides with respect to the minute transparent optical member 85.

Furthermore, the minute transparent optical member 85 is obliquelydisplaced by the driving member 35 to pass or totally reflect theincident light L1. Accordingly, the ON light and the OFF light can beseparated to the opposite sides with respect to the minute transparentoptical member 85 by obliquely displacing the minute transparent opticalmember 85 so that the incident angle of the incident light L1 incidentto the emission face 89 is smaller or larger than the critical angle.Since the light is totally reflected at the emission face 89 formed inthe minute transparent optical member 85, the total internal reflection(Total Internal Reflection) can be performed, so that light absorptioncan be reduced as compared with the reflection at the metal surface, andheating or degradation caused by high-intensity light can be prevented.Accordingly, an spatial light modulator adapted to light of ahigh-output light source can be implemented. Furthermore, themanufacturing process can be simplified as compared with the reflectionbased on formation of dielectric multi-layered film.

Furthermore, the optical path correcting member 91 for making theincident angle and the emission angle substantially coincident with eachother is provided in front of the light emission face of the minutetransparent optical member 85. Therefore, the emission light L2 (ONlight) which is separated to the opposite side to the incident light L1with respect to the minute transparent optical member 85 can be made tostraightly travel in the same direction as the incident light L1.Therefore, the optical design of the device using this modulator can befacilitated.

If a deflecting portion 93 having an asymmetric shape having a prismangle θo of about 35° is adopted as shown in FIGS. 24A and 24B, therecould be perform the normally-off control under which the incident lightL1 is passed through the emission face 89 under the initial state asshown in FIG. 24A, and the incident light L1 is totally reflected fromthe emission face 89 under the actuation state of the driving member 35as shown in FIG. 24B.

Next, a fifth embodiment of the transmission type spatial lightmodulator according to the present invention will be described. FIG. 25is a cross-sectional view showing the fifth embodiment using a prism asthe minute transparent optical member, FIG. 26 is a cross-sectional viewshowing a modification 1 of the fifth embodiment in which optical pathcorrecting member is provided, and FIG. 27 is a cross-sectional viewshowing a modification 2 of the fifth embodiment in which a prism havinga parallelogram shape is used.

In the transmission type spatial light modulator 400 of this embodiment,a deflecting portion 95 is designed in a prism-shape of a right-angledtriangle having a total reflection face as shown in FIGS. 25A to 25D. Inthe deflecting portion 95, one of the side portions between which theright angle is sandwiched is parallel to the movable film 37.Accordingly, as shown in FIG. 25A, the incident light L1 incident formthe movable film 37 is totally reflected from the total reflection face89 of the deflecting portion 95 at an angle of 90°, and emitted from theother side portion of the side portions between which the right angle issandwiched. That is, the incident light L1 is totally reflected by theprism, and deflected in a horizontal direction (in a direction parallelto the substrate 31).

In this transmission type spatial light modulator 400, as shown in FIG.25B, when the refractive index n=1.5 and the oblique displacement of themovable film 37, the inclination angle θr is equal to 10°, it is equalto 20° by the rotation in the positive and negative direction. In thiscase, the emission angle θe with respect to the inclination angle θe isalso equal to 10°, and the deflection angle θs shown in FIG. 25C isequal to 20°. This means that a larger deflection angle (θs=20°) can beachieved at a smaller inclination angle (2θr=20°) as compared with thetransmission type spatial light modulator 100 of the first embodimentwhich achieves the deflection angle θs=15° at the inclination angle2θr=30°. Accordingly, a displacement H of 1.8 μm is achieved at theposition located at a distance w=5.0 μm from the left end of thedeflecting portion 95 as shown in FIG. 25D.

As an application of the transmission type spatial light modulator 400,an optical path correcting member 91 a and an optical path correctingmember 91 b may be provided at the light emission face side of thedeflecting portion 95 so as to be spaced from each other through a gapas shown in FIG. 26. That is, an optical system is constructed by thecombination of a movable prism and a fixed prism. According to such aconstruction, ON light can be emitted from the front-surface protectionsubstrate 57 by the optical path correcting member 91 a in the case ofthe inclination angle θr<0°, OFF light can be emitted in the horizontaldirection in the case of the inclination angle θr=0°, and OFF light canbe emitted from the substrate 31 by the optical path correcting member91 b in the case of the inclination angle θr>0°. That is, since thedeflection angle θs can be increased by a small inclination angle θr,the deflected light is selectively introduced into the two optical pathcorrecting member 91 which are spaced from each other, whereby thedeflection in the same direction as the incident light L1, in theopposite direction to the incident light L1 and in the verticaldirection to the incident light L1 can be surely performed.

Since the deflecting portion 95 has a prism shape, a large deflectionangle (θs) can be achieved by a small inclination angle (θr).Furthermore, the reflection loss can be reduced, and the lightabsorption can be reduced as compared with the reflection at the metalsurface. Still furthermore, since the deflection angle is increased, amargin can be easily taken (the design limit is moderated), and thedegree of freedom of the optical design of an optical path or the likecan be enhanced. Accordingly, for example, an optical communicationdevice such as an optical switch for switching an optical path can beprovided at a low price.

As a modification of the transmission type spatial light modulator 400,two total reflection faces 89 a and 89 b are provided by using aparallelogram deflecting portion 97 as shown in FIG. 27. According tosuch a construction, ON light is emitted from the front-surfaceprotection substrate 57 by the total reflection faces 89 a and 89 b inthe case of the inclination angle θr<0°, OFF light can be emitted in anoblique upward direction from the total reflection face 89 b by thetotal reflection face 89 a in the case of the inclination angle θr=0°,and OFF light is emitted substantially in the horizontal direction fromthe total reflection face 89 b by the total reflection face 89 a.Accordingly, the OFF light is not returned to the incident side, and itcan be escaped to an area which has less influence on the other areas,so that a stray light treatment can be excellently performed.

Next, a sixth embodiment of the transmission type spatial lightmodulator according to the present invention will be described. FIGS.28A to 28C are cross-sectional views showing a sixth embodiment in whichthe light emission face of the minute transparent optical member has acurved-surface shape. In a transmission type spatial light modulator 500of this embodiment, at least a part of the light incident face or lightemission face of a minute transparent optical member 99 is designed in acurved-surface shape. In this embodiment, the light emission face isdesigned to have a convex curved-surface shape. That is, a deflectingportion 101 is designed in a convex-lens shape. The shape of thedeflecting portion 101 may be designed in a concave-lens shape or it maybe a Fresnel zone plate having a curved line portion which is coaxiallydifferent in curvature.

According to the transmission type spatial light modulator 500, at leasta part of the light incident face or light emission face is designed ina curved-surface shape. Therefore, the refractive index can becontinuously varied, and also the refractive index difference in arefractive index variable range can be increased (as a result, thedeflection angle difference can be increased).

Next, a seventh embodiment of the transmission type spatial lightmodulator according to the present invention will be described. FIGS.29A to 29C are cross-sectional views showing a seventh embodiment inwhich the minute transparent optical member has a refractive indexdistribution, and FIGS. 30A to 30C are cross-sectional views showing amodification of the seventh embodiment in which a refraction interfaceis designed to be a curved surface.

In a transmission type spatial light modulator 600 of this embodiment, aminute transparent optical member 103 has a refractive indexdistribution which is different in refractive index in the traveldirection of light. In addition, the light deflecting direction based onthe refractive index distribution is not parallel to the light traveldirection, and thus both the directions are different from each other.The minute transparent optical member 103 having such a characteristiccan be constructed by designing the whole of the minute transparentoptical member 103 or only the deflecting portion in a rectangularsectional shape as shown in FIGS. 29A to 29C, and making the refractiveindex n1 of an upper medium 103 a and the refractive index n2 of a lowermedium 103 b different from each other (for example, n1>n2) with a pairof diagonal lines as the boundary therebetween.

In the transmission type spatial light modulator 600, as shown in FIG.29B, under the initial condition that the driving member 35 is notactuated, the emission angle of the deflected light is θe1 for theinclination angle θr=0°. As shown in FIG. 29A, the driving member 35 isactuated, and the emission angle of the deflected light is θe2 for theinclination angle θr<0°. Furthermore, as shown in FIG. 29C, the drivingmember 35 is actuated, and the emission angle of the deflected light isθe3 for the inclination angle θr>0°. Here, by setting the refractiveindexes n1, n2 and the attachment face angle of the media 103 a, 103 b,“θe1≠θe2<θe3” can be established. That is, any deflection range can beset by setting a refractive index distribution or the like.

According to a transmission type spatial light modulator 600, a minutetransparent optical member 103 has a refractive index distribution inwhich the refractive index is varied in the light travel direction, andalso the light deflection direction achieved by the refractive indexdistribution is not parallel to the light travel direction, so that anydeflection range can be set by using a flat-plate type minutetransparent optical member 103. Furthermore, the thickness of the minutetransparent optical member 103 having a desired deflection range can bereduced, so that the modulator can be designed to be light in weight andhave high-speed response.

As a modification of the transmission type spatial light modulator 600,as shown in FIGS. 30A to 30C, a minute transparent optical member 105 isachieved by laminating two or more media (105 a, 105 b, 105 c, 105 d).In this case, the respective media are laminated so that the interfacesthereof are arranged in a coaxial arcuate shape, and they are designedso that a medium located at a near position to the center has a higherrefractive index. This construction has an effect of further increasingthe angle difference between (θe1≠θe2) and (θe3) as compared with theconstruction shown in FIGS. 29A to 29C.

Next, an eighth embodiment of the transmission type spatial lightmodulation array device according to the present invention will bedescribed. FIG. 31 is a cross-sectional view showing the transmissiontype spatial light modulation array device according to the eighthembodiment in which micro-lenses are integrated, and FIG. 32 is across-sectional view showing a modification of the transmission typespatial light modulation array device shown in FIG. 31 which is equippedwith two-stage micro-lenses.

The above transmission type spatial light modulators (100, 180, 181,182, 200, 300, 400, 500 or 600) may be arranged one-dimensionally ortwo-dimensionally to constitute a transmission type spatial lightmodulation array device 700. For example, the transmission type spatiallight modulators 300 having the same structure are arrangedone-dimensionally or two-dimensionally on the same movable elementsubstrate 111, whereby the transmission type spatial light modulationarray device 700 functions as one transmission type light deflectingdevice.

A transparent insulating film 113 is laminated on a movable elementdevice 111, and the above driving circuits (CMOS or the like) 115 arerespectively formed in the other area than the light transmission areaof the transparent insulating film 113 in connection with the respectivetransmission type spatial light modulators 300. Furthermore, amicro-lens array 117 is disposed and joined to the light incident faceof the movable element substrate 111 so as to confront the lightincident face of the movable element substrate 111 in parallel. Themicro-lens array 117 has plural micro-lenses 117 a corresponding to therespective transmission type spatial light modulators 300.

According to the transmission type spatial light modulation array device700, the transmission type spatial light modulators described above(100, 180, 181, 182, 200, 300, 400, 500 or 600) are one-dimensionally ortwo-dimensionally arranged and thus they function as one lightmodulation device. Therefore, they can optically modulate high-densitypixels at high speed in an application to a light exposure head, adisplay or the like. In addition, many transmission type spatial lightmodulators can be arranged with the same quality and high precision bythe semiconductor manufacturing process, so that image display, etc. canbe performed with high quality and high precision while aligningemission light.

The micro-lens array 117 having the plural micro-lenses 117 acorresponding to the respective transmission type spatial lightmodulators are arranged at the light incident face so as to confront thelight incident face, and thus the incident light flux can be narroweddown, so that the minute transparent optical member is miniaturized andreduced in weight, and the high-speed driving, the low-voltage drivingand the low power-consumption driving can be performed. Furthermore, ascompared with a case where no micro-lens 117 a is used, the minutetransparent optical member can be formed in a small area, and thus thedriving circuit area can be more easily secured when compared on theassumption of the same substrate area.

As a modification of the transmission type spatial light modulationarray device 700, other micro-lenses 117 b are formed on the sameoptical axis as the micro-lenses 117 a as shown in FIG. 32. In thisconstruction, the incident light flux is passed through the micro-lenses117 a, whereby the light converged to the focusing point is passedthrough the other micro-lenses 117 b as divergent light and collimatedlight is made incident to the movable element substrate 111.

Next, a ninth embodiment adopting the transmission type spatial lightmodulation array device of this invention as an exposure device will bedescribed. FIG. 33 is a diagram showing the construction of the exposuredevice of the ninth embodiment which uses the transmission type spatiallight modulation array device, FIG. 34 is a block diagram showing theexposure device shown in FIG. 33 and FIG. 35 is a diagram showing theoptical path of the exposure device shown in FIG. 33.

The transmission type spatial light modulation array device describedabove is suitably applicable to the exposure device 800 shown in FIG.33, for example. The transmission type spatial light modulation arraydevice 900 may be constructed by providing the micro-lens array 117 tothe transmission type spatial light modulators 100. The exposure device800 is equipped with a drum 123 for holding an exposure target 121 whileadsorbing the exposure target 121 on the outer peripheral surfacethereof, and an auxiliary scanning unit 127 which is freely movablysupported by a guide shaft 125 extending along the rotational axis ofthe exposure device 3. The drum 123 is counterclockwise rotated by arotational driving motor (not shown). The auxiliary scanning unit 127 ismoved in the right-and-left direction of FIG. 33 by a horizontal drivingmotor (not shown). Here, with respect to the exposure target 121, aD-direction based on the rotation of the drum 123 corresponds to a mainscanning direction, and an L-direction based on the movement of theauxiliary scanning unit 127 corresponds to an auxiliary scanningdirection.

As shown in FIG. 34, the auxiliary scanning unit 127 has alight-source/SLM (optical modulating) unit 129 and an imaging lenssystem 131. The rotational position of the drum 123 is detected by amain scanning position detector 133, and the moving position of theauxiliary scanning unit 127 is detected by an auxiliary scanningposition detector 135. The position signals detected by the mainscanning position detector 133 and the auxiliary scanning positiondetector 135 are input to a signal generator 137. The signal generator137 outputs a modulation signal and a light source signal to thelight-source/SLM unit 129 in accordance with an image signal transmittedfrom a superordinate controller on the basis of these position signals.The imaging lens system 131 is constructed by combined zoom lenses 131a, 1341 b for imaging a laser beam modulated and emitted from thelight-source/SLM unit 129 onto the surface of the exposure target 121while varying the magnification thereof.

In the light-source/SLM unit 129, plural transmission type spatial lightmodulators 100 are arranged in the auxiliary scanning direction in thetransmission type spatial light modulation array device 900. An opticalpath correcting member 141 is disposed at the light incident face sideof the transmission type spatial light modulation array device 900, andthe optical path correcting member 141 totally reflects or transmitsdeflected light emitted from the transmission type modulation arraydevice 900 by the emission face 141 a, thereby separating the light intoeffective light (ON light) and unnecessary light (OFF light).

Accordingly, when the exposure target 121 and the auxiliary scanningunit 127 are relatively moved in the direction (main scanning direction)perpendicular to the arrangement direction of the transmission typespatial light modulators 100, one-line pixels whose number is equal tothe arrangement number of the transmission type spatial light modulators100 can be exposed to ON light emitted form the emission face 141 ainthe same direction as described above. Image signals of one line aretransmitted as modulation signals and light source signals to thetransmission type spatial light modulators 100 together with themovement of the exposure target 121 in the main scanning direction, andthe respective transmission type spatial light modulators 100 arecontrolled to be turned on and off. Accordingly, the exposure lightemitted from the auxiliary scanning unit 127 is turned on and off, andexposure control is carried out on the exposure target 121 every pixelswhose number is equal to the number of the transmission type spatiallight modulators 100 in the main scanning direction, thereby carryingout the scan-exposure operation of one line. Thereafter, the auxiliaryscanning unit 127 is moved in the auxiliary scanning direction, and thesubsequent one line is successively exposed to light in the same manner.

As described above, according to the exposure device 800 having thetransmission type spatial light modulation array device 900, theincident light L1 is deflected at high speed by the transmission typespatial light modulation array device 900, and the deflected light isseparated into ON light and OFF light by the optical path correctingmember 141, whereby exposure or image recording can be carried out onthe exposure target 121. Furthermore, the deflected light can be emittedsubstantially in the straight direction by using the transmission typespatial light modulators 100, and it is not required to bend the opticalpath at a large angle, which is needed in the case of the reflectiontype spatial light modulator. Therefore, the optical system around themodulator can be disposed linearly and thus the compact design of thedevice can be facilitated.

The exposure target 121 may be not only a recording medium held bon thedrum 123, but also a screen. In this case, the driving of thetransmission type spatial light modulation array device 900 iscontrolled in accordance with an image signal, and emission light isprojected onto the screen through a projection lens. Accordingly, aprojector using the transmission type spatial light modulators can beachieved.

According to the transmission type spatial light modulator and thetransmission type spatial light modulation array device, the directionand light amount of the transmitted light can be controlled by a smalldisplacement amount, and high-speed deflection and low-voltage drivingcan be performed. Therefore, they are applicable to high-precision andhigh-resolution exposure head, display, etc.

1. A transmission type spatial light modulator comprising: an opticalmember that deflects and emits light in a direction different from anincident direction of incident light; a support member that supports theoptical member in a midair position so that a light emission facethereof can be inclined with respect to a plane perpendicular to atravel direction of the light incident direction; and driving memberthat obliquely displaces the optical member to vary the light emissiondirection from the optical member.
 2. The transmission type spatiallight modulator according to claim 1, wherein the optical member is aminute transparent optical member.
 3. The transmission type spatiallight modulator according to claim 1, wherein the driving membercontrols the driving member by an electrical mechanical operation. 4.The transmission type spatial light modulator according to claim 1,which further comprises a light shielding member that is disposed aheadof the light emission face of the optical member and shields anyemission light in a direction-variable range of light emitted from theoptical member.
 5. The transmission type spatial light modulatoraccording to claim 4, wherein the driving member obliquely displaces theoptical member to displace the emission light with respect to the lightshielding member, thereby varying an amount of transmission light of theemission light.
 6. The transmission type spatial light modulatoraccording to claim 1, wherein the optical member has a refractive indexlarger than 1, and a light incident surface and a light emission surfacehave non-parallel faces to each other.
 7. The transmission type spatiallight modulator according to claim 1, wherein the optical member has arefractive index distribution different in refractive index inaccordance with the light travel direction, and a light deflectiondirection based on the refractive index distribution is different fromthe light travel direction.
 8. The transmission type spatial lightmodulator according to claim 1, wherein the optical member has a totalreflection face that totally reflects the incident light.
 9. Thetransmission type spatial light modulator according to claim 8, whereinthe optical member is obliquely displaced by the driving member totransmit or totally reflect the incident light.
 10. The transmissiontype spatial light modulator according to claim 9, which furthercomprises an optical path correcting member that is disposed ahead ofthe light emission face of the optical member to make an incident angleand an emission angle substantially coincident with each other.
 11. Thetransmission type spatial light modulator according to claim 8, whereinthe optical member has a prism-shape.
 12. The transmission type spatiallight modulator according to claim 8, wherein at least a part of thelight incident face or light emission face of the optical member has acurved-surface shape.
 13. The transmission type spatial light modulatoraccording to claim 1, which further comprises: a first prism member thatreceives a emission light when the optical member is obliquely displacedby the driving member and the emission light is emitted from the opticalmember in a predetermined direction, and emits the emission light aseffective light while deflecting the emission light in a firstdirection; and a second prism member that receives a emission light whenthe optical member is obliquely displaced by the driving member and theemission light is emitted from the optical member in a directiondifferent from the predetermined direction, and deflects the emissionlight as unnecessary light in a second direction different from thefirst direction.
 14. The transmission type spatial light modulatoraccording to claim 1, wherein the driving member obliquely displaces theoptical member by electrostatic force.
 15. A transmission type spatiallight modulation array device comprising transmission type spatial lightmodulators according to claim 1, wherein the transmission type spatiallight modulators are arranged one-dimensionally or two-dimensionally.16. The transmission type spatial light modulation array deviceaccording to claim 15, wherein a micro-lens array having a plurality ofmicro-lenses disposed in connection with the respective transmissiontype spatial light modulators is disposed so as to confront the lightincident face.
 17. The transmission type spatial light modulatoraccording to claim 1, wherein the light emission direction is in thetravel direction of the light incident direction.
 18. The transmissiontype spatial light modulator according to claim 1, wherein the opticalmember is a transmission type light deflector, wherein the incidentlight and emission light exist at different sides with respect to theoptical member.
 19. The transmission type spatial light modulatoraccording to claim 1, wherein the driving member rotates the opticalmember in the midair position about an axis orthogonal to the traveldirection of the incident light.
 20. The transmission type spatial lightmodulator according to claim 1, wherein the optical member istransparent to the incident light.
 21. The transmission type spatiallight modulator according to claim 1, further including an air gap belowa light incident face, wherein the incident light passes through the airgap.
 22. The transmission type spatial light modulator according toclaim 4, wherein the light shielding member only shields emission lighthaving an emission angle within a predetermined range.
 23. Thetransmission type spatial light modulator according to claim 4, whereinthe light shielding member shields emission light by absorption.
 24. Thetransmission type spatial light modulator according to claim 7, whereinthe refractive index distribution includes a plurality of refractiveindices, distributed within the optical member in accordance with thelight travel direction.
 25. The transmission type spatial lightmodulator according to claim 7, wherein the refractive index iscontinuously varied within the optical member.
 26. The transmission typespatial light modulator according to claim 8, wherein the totalreflection face is an inner face of a light emission surface.
 27. Thetransmission type spatial light modulator according to claim 8, whereinthe incident light is totally reflected at an inner face of the opticalmember.
 28. The transmission type spatial light modulator according toclaim 9, wherein the optical member is obliquely displaced to switchbetween a transmission state and a total reflection state of theincident light.
 29. The transmission type spatial light modulatoraccording to claim 28, wherein during the transmission state, deflectedlight is emitted from an opposite side to the light incident face of theoptical member, and during the total reflection state, reflected lightis emitted from a light incident face side of the optical member. 30.The transmission type spatial light modulator according to claim 10,wherein an emitted light of the correcting member and the incident lightare substantially parallel to each other.